Matrix formulation of vector operations

An efficient technique is developed to simplify the computations in the area of vector analysis. The evaluation of vector algebraic and differential operations becomes more simple and straightforward by simply converting the vector operations into matrix operations. The matrix formulation technique is especially useful when there are mixed coordinate basis involved in the vector operations.     

本刊英文版Vol.30(2014),No.10论文摘要(英文)

<正>on Double Vector Bundles Zhuo CHEN Zhang Ju LIU Yun He SHENG Abstract In this paper,we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles.Moreover,operations on double vector bundles can be transferred to operations on the corresponding short exact sequences.In particular,we study the duality theory of double vector bundles in term of     

基于语言值的变权综合决策方法

给出一种新的语言值乘法和加法运算,同时利用扩展原理、格贴近度和择近原则等理论论证所给运算法则的科学性,在此基础上建立一个基于二元组的纯语言值加权综合决策模型,随后,在语言值与实数集[0,1]之间定义两个转换函数,由此引入语言值效用向量等概念,借助语言值效用向量和实数型状态变权向量导出语言值状态变权向量,进而建立相应的语言值变权公式和变权综合决策模型。     

On double vector bundles

In this paper, we construct a category of short exact sequences of vector bundles and prove that it is equivalent to the category of double vector bundles. Moreover, operations on double vector bundles can be transferred to operations on the corresponding short exact sequences. In particular, we study the duality theory of double vector bundles in term of the corresponding short exact sequences. Examples including the jet bundle and the Atiyah algebroid are discussed.     

Fast and Parallel Interval Arithmetic

Infimum-supremum interval arithmetic is widely used because of ease of implementation and narrow results. In this note we show that the overestimation of midpoint-radius interval arithmetic compared to power set operations is uniformly bounded by a factor 1.5 in radius. This is true for the four basic operations as well as for vector and matrix operations, over real and over complex numbers. Moreover, we describe an implementation of midpoint-radius interval arithmetic entirely using BLAS. Therefore, in particular, matrix operations are very fast on almost any computer, with minimal effort for the implementation. Especially, with the new definition it is seemingly the first time that full advantage can be taken of the speed of vector and parallel architectures. The algorithms have been implemented in the Matlab interval toolbox INTLAB.     

New Combinations of Convex Sets

The family of convex sets in a (finite dimensional) real vector space admits several unary and binary operations – dilatation, intersection, convex hull, vector sum – which preserve convexity. These generalize to convex functions, where there are in fact further operations of this kind. Some of the latter may be regarded as combinations of two such operations, acting on complementary subspaces. In this paper, a general theory of such mixed operations is introduced, and some of its consequences developed.     

Minkowski iteration of sets

The Minkowski addition, ⊕, is a natural generalization of vector addition. However, ⊕ and scalar multiplication do not follow all the usual laws of vector space operations. This is reflected upon the properties of a new operation, °, which maps vector sets into vector sets. The study of a linear iterative process (with ° acting recurrently on vector sets) brings out the outstanding value of vector balls and convex hulls for obtaining explicit solutions or bounds.     

Indecomposable representations for real roots of a wild quiver

For a given quiver and dimension vector, Kac has shown that there is exactly one indecomposable representation up to isomorphism if and only if this dimension vector is a positive real root. However, it is not clear how to compute these indecomposable representations in an explicit and minimal way, and the properties of these representations are mostly unknown. In this note we study representations of a particular wild quiver. We define operations which act on representations of this quiver, and using these operations we construct indecomposable representations for positive real roots, compute their endomorphism rings and show that these representations are tree representations. The operations correspond to the fundamental reflections in the Weyl group of the quiver. Our results are independent of the characteristic of the field.     

幂向量,复合向量数及其函数理论

本文提出向量为其幂向量和向量幂级数．向量幂级数由一实数和某一向量联合组成的“复合向量数”及其函数有重要涵义．这数也有运算法则．从复合向量数的函数理论分析知其函数有导数和解析函数的必要和充分条件．这些条件构成了“双曲型”方程的特征以及函数的积分性质等．     

On Felbin-type Fuzzy 2-normed Spacesand Its Fuzzy I-topologies

In this paper using the concept of Felbin-type fuzzy 2-norm ‖.,.‖ on a vector space,two I-topologies τ‖.,.‖ and τ*‖.,.‖ is constructed.After making our elementary observations on this fuzzy I-topologies,the continuity of vector space operations is discussed and it is proved that the vector space with I-topology τ‖.,.‖ is not I-topological vector space but with τ*‖.,.‖ is I-topological vector space.Next we study the relationship between this two I-topologies and it is proved that τ*‖.,.‖■τ‖.,.‖.     

Direct separation of two-dimensional vector fields into irrotational and solenoidal parts

An iterative technique is given for separating a two-dimensional vector into irrotational and solenoidal parts. In contrast to classical methods, the procedure operates directly on the orthogonal scalar components of the vector field, and gives the two separate fields as the result of a single sequence of operations. The manipulations are somewhat similar to a relaxation process. An example of the decomposition of a meteorological wind field is given.     

Symmetric centrosymmetric matrix–vector multiplication

We present a method for the multiplication of an arbitrary vector by a symmetric centrosymmetric matrix, requiring floating-point operations, rather than the 2n² operations needed in the case of an arbitrary matrix. Combining this method with Trench's algorithm for Toeplitz matrix inversion yields a method for solving Toeplitz systems with the same complexity as Levinson's algorithm.     

Construction of the vector space concept from the viewpoint of APOS theory

We apply APOS theory to propose a possible way that students might follow in order to construct the vector space concept. We describe the mental mechanisms and constructions that might take place when students are learning this concept. We then report on a study that we performed with 10 undergraduate mathematics students through the application of a questionnaire and an interview. In this paper we focus on the coordination between the two operations that form part of the vector space structure and the relation of the vector space schema to other concepts such as linear independence and binary operations.     

A method of desingularization for analytic two-dimensional vector field families

It is well known that isolated singularities of two dimensional analytic vector fields can be desingularized: after a finite number of blowing up operations we obtain a vector field that exhibits only elementary singularities. In the present paper we introduce a similar method to simplify the periodic limit sets of analytic families of vector fields. Although the method is applied here only to reduce to families in which the zero set has codimension at least two, we conjecture that it can be used in general. This is related to the famouss Hibert's problem about planar vector fields.     

基于学习向量量化神经网络的水环境质量综合评价

针对水环境质量综合评价中指标权重确定方法的不足,利用学习向量量化(LVQ)神经网络具有的强大的非线性运算和相似特征聚类功能,提出一种基于学习向量量化(LVQ)神经网络的水质综合评价决策方法.将它应用于水质综合指标评价,为改进水质综合评价提供了一种简捷的分类评价方法.     

An error-free algorithm to solve a linear system of polynomial equations

The paper presents an error-free algorithm to solve a system of linear equations with polynomial coefficients. Modular arithmetic in residual polynomial class and in residual numeric class is employed. The algorithm is iterative and well suited for implementation for computers with vector operations and fast and error-free convolutors.     

Vectorization and multitasking of nonlinear network programming algorithms

Vector supercomputers are designed with two levels of parallelism in order to achieved computational efficiency: low level parallelism through vector operations and high level parallelism with multiple independent processors. These innovations have a significant impact on the development of algorithms for network optimization.In this paper a framework for the vectorization and multitasking of optimization software is developed. It is then applied on the primal truncated Newton algorithm for nonlinear generalized network problems. The vectorization and multitasking of the algorithm is discussed and illustrated with computational experiments with the software system NLPNETG on the CRAY series of vector multiprocessors.     

Backward error analysis of an inexact Arnoldi method

We investigate the behavior of Arnoldi's method for Hermitian matrices in the case of inexact vector operations. A special purpose variant of Gram Schmidt orthogonalization is introduced which computes a nearly orthogonal Krylov subspace basis and additionally implicitly provides an exactly orthogonal basis. In the second part we perform a backward error analysis and show that the exactly orthogonal basis satisfies a Krylov relation for a perturbed system matrix. The norm of the backward error is shown to be on the level of the accuracy of the vector operations. (© 2013 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

向量到子空间的距离及其应用

给出了向量到有限维子空间距离的定义及求法 ,并推广到向量到可数无限维子空间距离 .采用两种方法求距离并比较了它们的运算量 .揭示了 Cholesky分解法与 Schmidt正交化方法的内在联系 .最后利用向量到子空间距离给出了矛盾方程组最小二乘解的求法